A fireproof construction element of the type shown from German industrial standard (DIN)4102 is normally made of steel. Only steel has been found to have the necessary fire resistance. Although aluminum is well known for use in the window frames, it has been found unsuitable for use in firecode construction since it melts at approximately 659.degree. C. This drawback of aluminum has been recognized as making it completely unsuitable for fireproof construction, in particular in window frames since the aluminum is said to soften and allow glass to drop out.